Could it be the church absorbing the prayers' power, and since Sei kept going there for a quiet long time, his own power was absorbed that caused his body to get weakened?? That's why Aresh immediately went to the church??
Could it be the church absorbing the prayers' power, and since Sei kept going there for a quiet long time, his own power was absorbed that caused his body to get weakened?? That's why Aresh immediately went to the church??